:root{
  --bg:#0f1916; --bg-2:#13201c; --surface:#172522; --line:#2a3f38; --line-2:#35534a;
  --ink:#eaf2ee; --ink-2:#b8cbc3; --ink-3:#8fa79d;
  --sage:#83bdaa; --sage-deep:#478d7d; --warn:#e8b27a;
  --ease-out:cubic-bezier(0.23,1,0.32,1);
  --display:"Unbounded Variable","Unbounded",system-ui,sans-serif;
  --body:"Onest Variable","Onest",system-ui,sans-serif;
  --mono:"JetBrains Mono Variable","JetBrains Mono",ui-monospace,monospace;
  color-scheme:dark;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth;-webkit-text-size-adjust:100%}
body{margin:0;background:var(--bg);color:var(--ink);font:400 1.0625rem/1.6 var(--body);-webkit-font-smoothing:antialiased;-webkit-tap-highlight-color:transparent}
::selection{background:var(--sage);color:#0c1411}
:focus-visible{outline:2px solid var(--sage);outline-offset:3px;border-radius:6px}
a{color:var(--sage);text-underline-offset:.2em;text-decoration-thickness:1px}
a:hover{color:var(--ink)}
html{scrollbar-color:var(--line-2) var(--bg)}
code,.mono{font-family:var(--mono);font-size:.92em}
.nowrap{white-space:nowrap}
.visually-hidden{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap}
.skip{position:absolute;left:1rem;top:-3rem;background:var(--sage);color:#0c1411;padding:.5rem .9rem;border-radius:8px;z-index:10}
.skip:focus{top:1rem}

.nav{position:sticky;top:0;z-index:5;display:flex;align-items:center;gap:2rem;padding:.9rem clamp(1.25rem,4vw,3rem);background:rgba(15,25,22,.86);backdrop-filter:saturate(1.4) blur(14px);-webkit-backdrop-filter:saturate(1.4) blur(14px);border-bottom:1px solid rgba(53,83,74,.5)}
.brand{white-space:nowrap;display:flex;align-items:center;gap:.65rem;color:var(--ink);text-decoration:none;font:600 1rem/1 var(--display);letter-spacing:-.01em}
.brand b{color:var(--sage);font-weight:600}
.nav nav{display:flex;gap:1.6rem;margin-left:auto}
.nav nav a{color:var(--ink-2);text-decoration:none;font-size:.95rem}
.nav nav a:hover{color:var(--ink)}

.btn{display:inline-flex;align-items:center;gap:.6rem;min-height:48px;padding:.8rem 1.35rem;border-radius:12px;font:600 1rem/1.1 var(--body);text-decoration:none;cursor:pointer;border:1px solid transparent;transition:transform 160ms var(--ease-out),background-color 200ms var(--ease-out),border-color 200ms var(--ease-out),box-shadow 200ms var(--ease-out);touch-action:manipulation;user-select:none}
.btn:active{transform:scale(0.97)}
.btn-primary{background:var(--sage);color:#0c1411;box-shadow:0 1px 0 rgba(255,255,255,.35) inset,0 10px 24px -12px rgba(131,189,170,.55)}
.btn-ghost{color:var(--ink);border-color:var(--line-2)}
.btn-sm{min-height:40px;padding:.55rem 1rem;font-size:.92rem;background:var(--surface);color:var(--ink);border-color:var(--line-2)}
@media (hover:hover) and (pointer:fine){
  .btn-primary:hover{background:#9bd0bf;color:#0c1411}
  .btn-ghost:hover,.btn-sm:hover{border-color:var(--sage-deep);background:var(--bg-2);color:var(--ink)}
}

main{max-width:1180px;margin:0 auto;padding:0 clamp(1.25rem,4vw,3rem)}
h1,h2{font-family:var(--display);font-weight:600;letter-spacing:-.025em;text-wrap:balance;margin:0}
h1{font-size:clamp(2.4rem,5.6vw,4.6rem);line-height:1.02;max-width:15ch}
h2{font-size:clamp(1.7rem,3.4vw,2.6rem);line-height:1.1;max-width:22ch}
p{text-wrap:pretty}

.hero{padding:clamp(3rem,6.5vw,5rem) 0 clamp(3rem,7vw,5rem)}
.lede{font-size:clamp(1.1rem,1.6vw,1.3rem);color:var(--ink-2);max-width:60ch;margin:1.6rem 0 2.2rem}
.wrong{color:var(--warn);text-decoration:line-through;text-decoration-color:rgba(232,178,122,.6)}
.right{color:var(--sage)}
.cta{display:flex;flex-wrap:wrap;gap:.8rem}
.meta{color:var(--ink-3);font-size:.92rem;margin:.9rem 0 0;font-variant-numeric:tabular-nums}

.demo{margin:clamp(3rem,6vw,4.5rem) 0 0;background:linear-gradient(180deg,var(--surface),var(--bg-2));border:1px solid var(--line-2);border-radius:16px;padding:0;overflow:hidden}
.demo-bar{display:flex;align-items:center;justify-content:space-between;padding:.85rem 1.25rem;border-bottom:1px solid var(--line)}
.demo-title{color:var(--ink-2);font-size:.92rem}
.layout-pill{font:600 .8rem/1 var(--mono);letter-spacing:.04em;padding:.45rem .65rem;border-radius:999px;background:var(--bg);border:1px solid var(--line-2);color:var(--sage);transition:background-color 240ms var(--ease-out),color 240ms var(--ease-out)}
.layout-pill.flash{background:var(--sage);color:#0c1411}
.demo-field{position:relative;padding:clamp(1.4rem,3vw,2.2rem) clamp(1.25rem,3vw,2rem);min-height:9.5rem;cursor:text}
.demo-out{font:500 clamp(1.5rem,3.6vw,2.6rem)/1.3 var(--mono);letter-spacing:-.01em;min-height:1.3em;word-break:break-word}
.demo-out .w{display:inline-block;white-space:pre}
.demo-out .fixed{color:var(--sage);animation:swap 260ms var(--ease-out)}
.demo-out .caret{display:inline-block;width:.08em;height:1.05em;background:var(--sage);vertical-align:-.15em;margin-left:.04em;animation:blink 1.1s steps(1) infinite}
@keyframes blink{50%{opacity:0}}
@keyframes swap{from{opacity:.2;filter:blur(6px);transform:translateY(.18em)}to{opacity:1;filter:blur(0);transform:none}}
.demo-in{position:absolute;inset:0;width:100%;height:100%;opacity:0;font-size:16px;border:0;cursor:text}
.demo-field:focus-within{box-shadow:inset 0 0 0 2px var(--sage-deep)}
.demo-field .hint{color:var(--ink-3)}
.demo figcaption{padding:.9rem 1.25rem 1.1rem;color:var(--ink-3);font-size:.88rem;border-top:1px solid var(--line)}

.section{padding:clamp(3.5rem,8vw,6rem) 0;border-top:1px solid var(--line)}
.section-head{display:flex;flex-wrap:wrap;align-items:end;justify-content:space-between;gap:1rem 3rem;margin-bottom:2.4rem}
.section-head p{color:var(--ink-2);max-width:42ch;margin:0}

.engines{border:1px solid var(--line-2);border-radius:16px;overflow:hidden}
.erow{display:grid;grid-template-columns:1.1fr 1.6fr .8fr 1.6fr;gap:1.5rem;padding:1.35rem 1.5rem;border-top:1px solid var(--line);align-items:start}
.erow:first-child{border-top:0}
.ehead{background:var(--bg-2);color:var(--ink-3);font-size:.8rem;letter-spacing:.06em;text-transform:uppercase;padding:.85rem 1.5rem}
.erow span{color:var(--ink-2)}
.ename b{display:block;color:var(--ink);font:600 1.15rem/1.2 var(--display);letter-spacing:-.01em}
.ename small{color:var(--ink-3);font-size:.88rem}
.tag{font-style:normal;font-size:.85rem;padding:.25rem .6rem;border-radius:999px;border:1px solid var(--line-2);color:var(--ink-2);white-space:nowrap}
.tag.ok{color:var(--sage);border-color:var(--sage-deep)}

.split{display:grid;grid-template-columns:1fr 1.2fr;gap:3rem}
.split p{color:var(--ink-2);max-width:40ch}
.steps{list-style:none;counter-reset:s;margin:0;padding:0}
.steps li{counter-increment:s;position:relative;padding:0 0 1.5rem 3.4rem;color:var(--ink-2)}
.steps li::before{content:counter(s);position:absolute;left:0;top:-.15rem;width:2.3rem;height:2.3rem;display:grid;place-items:center;border-radius:10px;background:var(--surface);border:1px solid var(--line-2);font:600 .95rem/1 var(--mono);color:var(--sage)}
.steps li:not(:last-child)::after{content:"";position:absolute;left:1.15rem;top:2.4rem;bottom:.35rem;width:1px;background:var(--line-2)}
.steps b{color:var(--ink);font-weight:600}

.hotkeys{list-style:none;margin:0;padding:0;display:grid;grid-template-columns:repeat(2,1fr);gap:0 3rem}
.hotkeys li{display:grid;grid-template-columns:15.5rem 1fr;align-items:center;gap:1.5rem;padding:1.1rem 0;border-bottom:1px solid var(--line);color:var(--ink-2)}
.combo{display:flex;gap:.4rem;flex-shrink:0}
kbd{display:inline-grid;place-items:center;min-width:2.6rem;height:2.6rem;padding:0 .7rem;font:600 .85rem/1 var(--mono);color:var(--ink);background:linear-gradient(180deg,#22352f,#1a2a25);border:1px solid var(--line-2);border-bottom-width:3px;border-radius:9px;box-shadow:0 2px 4px rgba(0,0,0,.35);transition:transform 120ms var(--ease-out),border-bottom-width 120ms var(--ease-out)}
kbd.wide{min-width:5.2rem}
@media (hover:hover) and (pointer:fine){.hotkeys li:hover kbd{transform:translateY(1px);border-bottom-width:2px}}

.privacy h2{max-width:24ch;margin-bottom:2.6rem}
.facts{margin:0;display:grid;grid-template-columns:repeat(3,1fr);gap:2.2rem 3rem}
.facts dt{font:600 1rem/1.3 var(--display);color:var(--sage);margin-bottom:.45rem}
.facts dd{margin:0;color:var(--ink-2)}
.facts code{color:var(--ink);word-break:break-all}

.more h2{margin-bottom:2rem}
.ticks{list-style:none;margin:0;padding:0;columns:2;column-gap:3rem}
.ticks li{break-inside:avoid;position:relative;padding:0 0 1.1rem 1.8rem;color:var(--ink-2)}
.ticks li::before{content:"";position:absolute;left:0;top:.5rem;width:.75rem;height:.4rem;border-left:2px solid var(--sage);border-bottom:2px solid var(--sage);transform:rotate(-45deg)}
.ticks .mono{color:var(--ink)}

.final{padding:clamp(4rem,10vw,7.5rem) 0;border-top:1px solid var(--line);text-align:left}
.final h2{font-size:clamp(2rem,5vw,3.8rem);max-width:18ch;margin-bottom:2rem}
.final .mono{font-size:.85em}
.build{margin-top:2.6rem;max-width:44rem;border-top:1px solid var(--line);padding-top:1.2rem;color:var(--ink-2)}
.build summary{cursor:pointer;color:var(--ink);font-weight:600}
.build pre{background:var(--bg-2);border:1px solid var(--line);border-radius:12px;padding:1rem 1.2rem;overflow:auto;font-size:.9rem;color:var(--ink)}

.foot{max-width:1180px;margin:0 auto;display:flex;flex-wrap:wrap;gap:1rem 2rem;padding:2rem clamp(1.25rem,4vw,3rem) calc(2rem + env(safe-area-inset-bottom));color:var(--ink-3);font-size:.9rem;border-top:1px solid var(--line)}
.foot span{margin-right:auto}
.foot a{color:var(--ink-2)}

@media (max-width:900px){
  .nav nav{display:none}
  .nav .btn-sm{margin-left:auto}
  .erow{grid-template-columns:1fr 1fr;gap:.6rem 1.2rem}
  .ehead{display:none}
  .erow .ename{grid-column:1/-1}
  .split{grid-template-columns:1fr;gap:1.5rem}
  .hotkeys{grid-template-columns:1fr}
  .facts{grid-template-columns:1fr 1fr}
  .ticks{columns:1}
}
@media (max-width:560px){
  .facts{grid-template-columns:1fr}
  .erow{grid-template-columns:1fr}
  .hotkeys li{grid-template-columns:1fr;gap:.7rem}
  .btn{width:100%;justify-content:center}
  .nav .btn{display:none}
}
@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{animation-duration:1ms!important;animation-iteration-count:1!important;transition-duration:1ms!important}
  .demo-out .caret{animation:none}
}

/* ---------- v2 additions ---------- */
.ic{width:1.15em;height:1.15em;flex-shrink:0}
.notwin{display:flex;flex-wrap:wrap;align-items:center;gap:.6rem 1rem;margin-top:1.2rem;padding:.9rem 1rem;border:1px dashed var(--line-2);border-radius:12px;max-width:44rem;color:var(--ink-2);font-size:.95rem}
.notwin[hidden]{display:none}
.notwin p{margin:0;flex:1 1 18rem}
.btn-sm2{min-height:40px;padding:.5rem .9rem;font-size:.9rem}
.btn.done,.copy.done{border-color:var(--sage-deep);color:var(--sage)}

/* keyboard */
.kb{--gap:clamp(3px,.55vw,7px);display:grid;gap:var(--gap);padding:0 clamp(1rem,3vw,2rem) clamp(1.2rem,2.6vw,1.8rem);user-select:none}
.kb-row{display:flex;gap:var(--gap);--kw:calc((100% - 11 * var(--gap)) / 12)}
.kb-row .k{flex:0 0 var(--kw)}
.kb-row.r1{padding-left:calc(var(--kw) * .4)}
.kb-row.r2{padding-left:calc(var(--kw) * .9)}
.kb-row.r3{justify-content:center}
.k{position:relative;aspect-ratio:1/0.92;border-radius:clamp(5px,.7vw,9px);background:linear-gradient(180deg,#1f302b,#18261f);border:1px solid var(--line);border-bottom-width:3px;box-shadow:0 2px 3px rgba(0,0,0,.3);transition:transform 120ms var(--ease-out),border-color 260ms var(--ease-out),background-color 260ms var(--ease-out),box-shadow 260ms var(--ease-out)}
.k b,.k i{position:absolute;font:600 clamp(.55rem,1.15vw,.95rem)/1 var(--mono);font-style:normal;transition:color 300ms var(--ease-out),opacity 300ms var(--ease-out),transform 300ms var(--ease-out)}
.k b{left:14%;top:14%}
.k i{right:14%;bottom:16%}
.kb[data-layout="en"] .k b{color:var(--ink)}
.kb[data-layout="en"] .k i{color:var(--ink-3);opacity:.7}
.kb[data-layout="uk"] .k b{color:var(--ink-3);opacity:.7}
.kb[data-layout="uk"] .k i{color:var(--sage);transform:scale(1.12)}
.kb-row .k.space{flex:0 0 52%;aspect-ratio:auto;height:clamp(1.6rem,3.4vw,2.6rem);display:grid;place-items:center}
.k.space b{position:static;color:var(--ink-3)!important;opacity:1!important;font-size:clamp(.55rem,1vw,.8rem)}
.k.on{transform:translateY(2px);border-bottom-width:1px;background:linear-gradient(180deg,#2b4a40,#213a32);border-color:var(--sage-deep);box-shadow:0 0 0 1px rgba(131,189,170,.25),0 6px 16px -8px rgba(131,189,170,.6)}

/* hotkey practice */
.kb-hint{color:var(--sage)}
.hotkeys li{transition:background-color 300ms var(--ease-out)}
.hotkeys li.hit{background:linear-gradient(90deg,rgba(131,189,170,.12),transparent 70%)}
.hotkeys li.hit kbd{transform:translateY(2px);border-bottom-width:1px;border-color:var(--sage-deep);color:var(--sage)}
.hotkeys li.hit > span:last-child{color:var(--ink)}

/* privacy proof */
.proof{margin-top:3.2rem;padding:clamp(1.4rem,3vw,2.2rem);border:1px solid var(--line-2);border-radius:16px;background:linear-gradient(180deg,var(--surface),var(--bg-2))}
.proof-head{display:flex;flex-wrap:wrap;gap:.6rem 3rem;align-items:baseline;margin-bottom:1.6rem}
.proof h3{margin:0;font:600 1.25rem/1.2 var(--display);letter-spacing:-.01em}
.proof-head p{margin:0;color:var(--ink-2);max-width:62ch}
.proof-grid{display:grid;grid-template-columns:1fr 1fr;gap:1.2rem}
.pf{display:grid;gap:.5rem}
.pf-l{font-size:.9rem;color:var(--ink-2)}
.pf input{font:500 1.15rem/1.2 var(--mono);color:var(--ink);background:var(--bg);border:1px solid var(--line-2);border-radius:12px;padding:.85rem 1rem;min-height:52px;caret-color:var(--sage);transition:border-color 200ms var(--ease-out),box-shadow 200ms var(--ease-out)}
.pf input::placeholder{color:var(--ink-3);opacity:.6}
.pf input:focus{outline:none;border-color:var(--sage-deep);box-shadow:0 0 0 3px rgba(71,141,125,.25)}
.pf input.flash{animation:pfflash 600ms var(--ease-out)}
@keyframes pfflash{0%{box-shadow:0 0 0 3px rgba(131,189,170,.55)}100%{box-shadow:0 0 0 3px rgba(71,141,125,.25)}}
.pf-s{font-size:.85rem;color:var(--ink-3);font-variant-numeric:tabular-nums}
.pf-s.ok{color:var(--sage)}

/* code copy */
.codebox{position:relative}
.copy{position:absolute;top:.55rem;right:.55rem;display:inline-flex;align-items:center;gap:.4rem;padding:.4rem .65rem;font:500 .8rem/1 var(--body);color:var(--ink-2);background:var(--surface);border:1px solid var(--line-2);border-radius:8px;cursor:pointer;transition:transform 140ms var(--ease-out),color 200ms,border-color 200ms}
.copy:active{transform:scale(0.96)}
.build pre{padding-right:7.5rem}

@media (max-width:900px){.proof-grid{grid-template-columns:1fr}}
@media (max-width:560px){.kb{padding-left:.8rem;padding-right:.8rem}.k b,.k i{font-size:.5rem}}

/* ---------- v3 scroll motion ---------- */
.motion .steps li::before{transform:scale(.7);opacity:0;transition:transform 520ms var(--ease-out),opacity 320ms var(--ease-out),background-color 600ms var(--ease-out),color 600ms var(--ease-out),border-color 600ms var(--ease-out);transition-delay:calc(var(--i,0)*160ms)}
.motion .steps li:not(:last-child)::after{transform:scaleY(0);transform-origin:top;transition:transform 600ms var(--ease-out);transition-delay:calc(var(--i,0)*160ms + 220ms)}
.motion .steps li{opacity:.35;transition:opacity 500ms var(--ease-out);transition-delay:calc(var(--i,0)*160ms + 80ms)}
.motion .steps.in li{opacity:1}
.motion .steps.in li::before{transform:none;opacity:1;animation:stepglow 900ms var(--ease-out) both;animation-delay:calc(var(--i,0)*160ms + 120ms)}
.motion .steps.in li:not(:last-child)::after{transform:none}
@keyframes stepglow{0%{background:var(--sage-deep);color:#0f1916;border-color:var(--sage);box-shadow:0 0 0 0 rgba(131,189,170,.5)}60%{box-shadow:0 0 0 8px rgba(131,189,170,0)}100%{background:var(--surface);color:var(--sage);border-color:var(--line-2);box-shadow:0 0 0 0 rgba(131,189,170,0)}}
.num{font-variant-numeric:tabular-nums}
.motion .hotkeys li.chord kbd{animation:keypress 620ms var(--ease-out) both;animation-delay:calc(var(--k,0)*110ms)}
@keyframes keypress{0%{transform:none}25%{transform:translateY(2px);border-bottom-width:1px;border-color:var(--sage-deep);color:var(--sage);box-shadow:0 0 0 3px rgba(131,189,170,.18)}70%{transform:translateY(2px);border-bottom-width:1px;border-color:var(--sage-deep);color:var(--sage)}100%{transform:none}}
.motion .btn.shine{position:relative;overflow:hidden}
.motion .btn.shine::after{content:"";position:absolute;inset:0;background:linear-gradient(100deg,transparent 30%,rgba(255,255,255,.35) 50%,transparent 70%);transform:translateX(-110%);animation:sheen 1100ms var(--ease-out) 200ms both;pointer-events:none}
@keyframes sheen{to{transform:translateX(110%)}}
@media (prefers-reduced-motion:reduce){
  .motion .steps li,.motion .steps li::before{opacity:1;transform:none}
  .motion .steps li:not(:last-child)::after{transform:none}
  .motion .steps.in li::before,.motion .hotkeys li.chord kbd,.motion .btn.shine::after{animation:none}
}

/* ---------- FAQ ---------- */
.faq h2{margin-bottom:2rem}
.qas{display:grid;grid-template-columns:repeat(2,1fr);gap:2rem 3rem}
.qa h3{font-size:1.05rem;line-height:1.35;margin:0 0 .5rem;color:var(--ink)}
.qa p{margin:0;color:var(--ink-2);max-width:38rem}
@media (max-width:760px){.qas{grid-template-columns:1fr;gap:1.6rem}}